<template>
<div>
    <router-link
     tag="div" to="/"
     class="header-abs"
     v-show="showAbs"
    >
        <div class='iconfont header-abs-back'>&#xe624;</div>
    </router-link>
    <div
     class="header-fixed"
     v-show="!showAbs"
     :style="opacityStyle"
    >
      景点详情
      <router-link to="/">
        <div class='iconfont header-back'>&#xe624;</div>
      </router-link>
    </div>
</div>
</template>
<script>
export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop
      if (top > 60) {
        const opacity = (top / 140) > 1 ? 1 : (top / 140)
        this.showAbs = false
        this.opacityStyle.opacity = opacity
      } else {
        this.showAbs = true
      }
    }
  },
  activated () {
    window.addEventListener('scroll', this.handleScroll)
  },
  deactivated () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>
<style lang="stylus" scoped>
  @import '~styles/varibles.styl'
    .header-abs
        position: absolute
        left: .2rem
        top: .2rem
        width: .8rem
        height: .8rem
        border-radius: .4rem
        background: rgba(0,0,0,.8)
        .header-abs-back
            color: #fff
            line-height: .8rem
            text-align: center
    .header-fixed
      z-index: 2
      position: fixed
      left: 0
      right: 0
      top: 0
      height: $headerHeight
      line-height: $headerHeight
      text-align: center
      color: #fff
      background: $bgColor
      font-size: .32rem
      .header-back
        position: absolute
        left: 0
        top: 0
        width: .64rem
        text-align: center
        font-size: .4rem
        color: #fff
</style>
